Known methods of depositing a coating on a substrate include die coating, knife-edge or notched-bar coating, spin coating, spray coating, gravure roll coating, and screen printing. Conventional die coating techniques are applicable only for wet thicknesses greater than about 25 .mu.m, and knife-edge or notched-bar coating techniques are suitable only for wet coating thicknesses greater than about 75 .mu.m. Spin coating onto microstructure surfaces, i.e., surfaces having structures in the size range of less than about 100 .mu.m, typically results in coating defects and non-uniform coating thicknesses due to the interaction between the microstructure and the radial fluid flow profile. Spray coating results in local non-uniformities in very small thickness applications, and the overspray interferes with the selective coating process. Conventional gravure roll coating is generally not applicable in selective coating patterns, although small wet thickness layers are attainable. Screen coating can generate patterned layers, but screen registration with the microstructure is critical, and this technique is not generally applicable to wet layers under 25 .mu.m thick.
It is often desirable to be able to apply a very thin, uniform coating to the lower surface of a microstructure bilevel substrate, e.g., between the ridges on the substrate. In a liquid crystal display (LCD), it is desirable to apply an alignment layer to the LCD panel in the areas between adjacent ridges on the LCD panel. The alignment layer induces molecular orientation in the liquid crystal which results in the necessary electro-optic response of the device. A uniform layer thickness of less than about 0.2 .mu.m, and preferably about 0.1 .mu.m, is required for uniformity of optical performance over the entire area of the LCD.